Math

A field doesn't have to hold a fixed number — it can hold a formula. Same idea as a spreadsheet cell: type a formula instead of a number.

Use another value

cabinetWidth - 36      // follows the cabinet width
height / 2             // exactly half the height
boards * thickness + (boards - 1) * gap

Arithmetic

Write	Means
`+ -`	add, subtract
`* /`	multiply, divide
`%`	remainder
`**`	power — width ** 2
`( )`	group — (a + b) / 2

Compare and choose

doorCount > 1 ? 2 : 1     // two handles on a double door, else one
width > 800 ? 3 : 2       // an extra shelf on wide cabinets

Ready-made helpers

Helper	Gives
`Math.max(a, b)`	the bigger of two numbers
`Math.min(a, b)`	the smaller — cap a size
`Math.round(x)`	nearest whole number
`Math.sqrt(aa + bb)`	diagonal length
`Curve.length(edge)`	length of a line you drew

Everyday recipes

You want	Formula
Half of something	`width / 2`
Inside width (two walls)	`width - 2 * thickness`
Equal gaps	`(width - parts * board) / (parts + 1)`
Cap a maximum	`Math.min(width, 1200)`
Switch a part off	`hasBack ? thickness : 0`

Need lists or rules that pick faces/edges? That's Expression.